Wind Turbines and Bat Mortality: Rotor Detectability Profiles

Bat mortality at wind turbine installations has been claimed to be an increasing problem and an obstacle to the growth of the wind industry, the mitigation of which is of great importance to the sector. The phenomenon of bat-turbine interaction appears widespread and is not well understood. This paper proposes the use of some fundamental analytical methods that estimate a bat's ability to detect and potentially avoid the moving blades of an operational turbine rotor. These equations are applied to selected models of existing turbines and microturbines. A 'rotor rating' system is proposed that could assist the evaluation of current and future turbine designs in terms of maximising the bat's chance of blade detection. It is shown that features such as rotor angular velocity, number of blades, blade width and bat species influence the likelihood of rotor detection.